JPH04189725A - Covering of container - Google Patents

Abstract

PURPOSE:To obtain a cap good in tightness and appearance, save resources and costs and prevent invasion of dust and dirt by a method wherein film is heated to shrink at a part which is in contact with a peripheral side of a corner of a container and further heated to shrink at parts which are in contact with the rest of the peripheral sides or all the peripheral sides to make covering. CONSTITUTION:Thermo-shrinking film 8 larger than a lid part surrounded by an upper edge 4 of a container 1 is covered on the lid part and fixed on the upper edge 4 of the container 1 by a pressing plate 9. The pressing plate 9 is controlled to be lower than a shrinking start temperature of the film, so that film at the lid part does not shrink before a peripheral part 10 of the film shrinks by heat. Before a whole shrinking of the film, thermo-shrinking film 11 which is in contact with a peripheral side of a corner 3 of the container is heated to shrink by hot air or heat rays. The film 11 is arranged along a peripheral side of a side part by stretching film 13 which is attached tight on the peripheral side of the corner 3 and in contact with the peripheral side of a side part 2 in a direction of a length of the side part. Then, the films 11 and 13 which are in contact with the peripheral sides of the side part 2 and the corner part 3 are heated to shrink.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method of shrinking a heat-shrinkable film to cover a polygonal container provided with an outlet.

[Conventional technology] Beverages in metal cans, puddings and jellies in vacuum-formed containers, beverages in paper containers, instant foods, etc. are sold in vending machines and stores, but the covered surface of the container is prone to dust and dirt. Alternatively, since bacteria or the like may adhere to the material, capping of the material is performed. Conventionally, ■ a cap molded from an unstretched thermoplastic resin film is placed over a container by just fitting it, ■ a cap molded using thermoplastic resin Koshipound is placed over a container by fitting it, and ■ heat shrinkage. The method used is to heat-shrink the film and cover the container lid. However, since methods ① and ② involve only fitting, it is easy for dust, dirt, bacteria, etc. to enter through the gaps and cause contamination.
Furthermore, since the cap is thick, it has disadvantages such as not being resource-saving.

Method (2) has the characteristics that the heat-shrinkable film has good adhesion to the circumference of the container, does not allow dirt to enter, does not come off during transportation, and does not allow water to enter even when immersed in water. There is a drawback that capping cannot be achieved properly unless the shape of the container lid is a curved shape such as a circle or an ellipse.

[Problems to be Solved by the Invention] The present invention provides a method for covering the lid of a container in which the surface with the outlet, which corresponds to the lid in a polygonal manner, has excellent sealability and appearance. It is on offer.

[Means for Solving the Problems] When covering the surface of a container having a polygonal surface with an outlet with a heat-shrinkable film, heat-shrink the portion of the film that comes into contact with the circumferential side of the corner of the container, Then, the remaining circumferential side or the entire circumferential side of the container is covered by heating and shrinking the portion that comes into contact with the container. This is a method of covering containers.

[Function] The heat-shrinkable film used in the present invention has a thickness of 15 to 200 μm and is made of a single layer or a composite layer of polyvinyl chloride, polyethylene, polypropylene, polystyrene, polycarbonate, polyester, etc.
It is a thermoplastic resin film stretched at a stretching ratio of

A uniaxially stretched film may be used, but a biaxially stretched film is preferable. Furthermore, the above-mentioned heat-shrinkable film provided with an adhesive layer such as a hot-melt adhesive may also be used.

Containers with polygonal faces and an outlet to which the method of the present invention is applied can be of various shapes, most commonly cubes, rectangular parallelepipeds, polygons, triangular prisms, square prisms, etc. In addition to column-shaped containers with an outlet on the top, and so-called pull-top containers in which the outlet on the top is lifted up and removed, there are also containers where the outlet is polygonal but gradually changes to a round shape toward the other surfaces. There are some variations on this. The corners of polygons also vary depending on the design, ranging from sharp corners to curved corners.

This will be explained below with reference to illustrative drawings.

FIG. 1 is a diagram showing an example of a container to which the method of the present invention is applied. Figure 2 shows a heat-shrinkable film covering the lid of the container.
It is an elevational view held down with a holding plate.

FIG. 3 is a plan view of the container lid covered with the above film and a diagram showing the process of shrinking the corners. FIG. 4 is an elevational view of the state after the corner circumferential side has been contracted. FIG. 5 is a diagram showing the process of shrinking the entire circumferential side.

An outlet 5 surrounded by an upper edge 4 consisting of a side 2.2'' of the straight portion of the container 1 shown in FIG. 1 and a corner 3 having a predetermined curvature.
When covering the lid part 6 and the peripheral side 7.7" of the lid part with a heat shrink film, the heat shrinkage is larger than that of the lid part surrounded by the upper edge 4 of the container 1, as shown in FIG. Cover the lid with the film 8, and then press the film against the upper edge 4 of the container with the presser plate 9.
Fixed to. The pressing plate 9 is controlled to a temperature below the shrinkage start temperature of the heat-shrinkable film, and prevents the film in the lid portion from shrinking before the peripheral portion 10 of the film shrinks due to heat. As shown in FIG. 3, before shrinking the entire container, the heat-shrinkable film 11 that contacts the circumferential side of the corner 3 of the container is heat-shrinked. Heat source is hot air 1
2 or a hot wire may be used. As a result, as shown in FIG. The film 13 is pulled in the length direction of the film 13, and the film 13 is disposed along the circumferential side of the side portion. Next, the fifth
As shown in the figure, the heat-shrinkable films 11 and 13 that are in contact with the peripheral sides of the side portions 2 and corner portions 3 are heat-shrinked. At this time, if the film that comes into contact with the circumferential side of the corner part 3 has already shrunk sufficiently, it is possible to heat only the part that comes into contact with the remaining circumferential side other than the circumferential side of the corner part 3 instead of the entire circumferential side. . The heat source may be hot air 14 or hot wire as in the previous step. In the conventional method of shrinking the entire periphery at once, the film in contact with the straight edge has weak adhesion to the container and has a large degree of freedom in shrinkage and deformation, causing the film to curl upward or rise above the top edge of the container. , it was not possible to make a capping with a good appearance.

When the heat-shrinkable film is shrunk in two stages as in this method, the film at the corners, which has strong adhesion to the container, is heat-shrinked in the previous process, and the film at the sides shrinks along its periphery. Because of this arrangement, the degree of freedom of deformation during heat shrinkage in the post-process is limited. Therefore, even though the film is made of a straight line, the film that comes into contact with the peripheral side of the side part does not curl upward and does not rise above the upper edge of the container.

In this way, after covering the lid of the container with the heat-shrinkable film, when the heat-shrinkable film is heat-shrinked to tightly cover the lid of the container and the periphery of the lid, the heat-shrinkable film is applied to the periphery of the corner. The heat-shrinkable film covering method is characterized by first heat-shrinking the heat-shrinkable film that is in contact with it, and then heat-shrinking the heat-shrinkable film that is in contact with the edge or the entire periphery, which improves adhesion and appearance. A good cap is completed.

[Effects of the Invention] According to the method of the present invention, a cap with good adhesion and good appearance can be made even if the surface with the outlet is polygonal, so it is resource-saving and low-cost, and there is no intrusion of dust or dirt. , it is possible to sell foods in sanitary containers that do not get damaged during transportation.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of a container to which the method of the present invention is applied. Figure 2 shows a heat-shrinkable film covering the lid of the container.
It is an elevational view held down with a holding plate. FIG. 3 is a plan view of the container lid covered with the above film and a diagram showing a step of shrinking the corner circumferential side. FIG. 4 is an elevational view of the state after the corner circumferential side has been contracted. FIG. 5 is a diagram showing the process of shrinking the entire circumferential side. 1...Container 2.2゛...Side part 3...
・Corner 4...Top edge 5...Outlet
6... Lid part 7. 7'... Lid part peripheral side 8.
・・Heat-shrinkable film 9 ・・Pressure plate 10
...Film peripheral portion 11...Film 12 in contact with the corner circumference side...Hot air 13...Film 14 in contact with the side circumference side...Hot air patent applicant Sumitomo Bakelite Co., Ltd. No. 1 Figure 2 Figure 3

Claims (1)

[Claims] (1) When covering the polygonal surface of a container with an outlet with a heat-shrinkable film, heat-shrink the portion of the film that contacts the container corner circumference, and then cover the remaining circumference of the container. A method for covering a container, comprising heating and shrinking the portion that contacts the side or the entire circumference.